Method for inserting weft in shuttleless looms

ABSTRACT

A method for laying weft thread in the warp shed used in needle looms is disclosed. This method consists in that the feeding and the receiving laying needles mutually reciprocate to transfer the weft thread at the moment of their closest approach. The needles meet at the midpoint of the distance between the starting points of their reciprocating movement for which purpose the needles are made different in length. The shorter needle is introduced into the warp shed with a time lag relative to the moment of inserting the longer needle thereinto, thus making the needles move in one direction while the weft thread is transferred, whereupon the needles return to their initial positions leaving the warp shed at the same time. At the expense of extending the time of contact of the needles during their movement in one direction, this method permits of significantly improving the conditions for catching the weft and sharply reducing the number of mispicks, loops, and double threads.

Galkin et al.

" 1111 3,826,289 [4 July 30, 1974 METHOD FOR INSERTING WEFT IN PrimaryExaminer-Henry S. Jaudon SHUTTLELESS LOOMS Attorney, Agent, orFirm-Holman & Stern [76] Inventors: Pavel Vladimirovich Galkin, ul. 1

proezd, la; Nikolai Antonovich ABSTRACT Rudenko, ul. Lesnaya, 4, kv. l0,A method for [a f ymg we t thread in the warp shed used both of Khmovskin needle looms is disclosed. This method consists in [22] Fil d; A 25,1972 thaltl the feeding and thereiceivilng layfinghneegles m:- tua yreciprocate to trans er t e wet t rea at t e [2]] Appl' 283757 moment oftheir closest approach. The needles meet at the midpoint of the distancebetween the starting [30] Foreign Application P i it D t points of theirreciprocating movement for which pur- 15 1971 USS 1724106 pose theneedles are made different in length. The shorter needle is introducedinto the warp shed with a [52 us. (:1 139/127 R time lag relative) themoment insertingethe longer 51 1 1m. 01 l)03d 47/18 needle therein),making the needles move in one [58] Field of Search 139/122 123 124 Rdirection while the weft thread is transferred, where- 139/127 i P uponthe needles return to their initial positions leaving the warp shed'atthe same'time. At the expense of [56] References Cited extending thetime of contact of the needles during their movement in one direction,this method permits UNITED STATES PATENTS of significantly improving theconditions for catching 322%? 1323 2 y l the weft and sharply reducingthe number of mispicks,

l'C S 3762.449 10/1973 Eilhaucr et ul. 139 127 loops and double threads3 Claims, 3 Drawing Figures 1 5 H I 5 IIllllllllllllllllllllllllllllllllllllllllillllll lllllllllllllllllllllllllll]llllllIllllllllIlllllllllllllllllllllllllllllllllllllllllllllllllll METHOD FOR INSERTING WEFT IN SHUTTLELESS LOOMSBACKGROUND OF THE INVENTION The present invention relates to methods forlaying weft threads in the warp shed of a loom which may find wideapplication in weaving on needle looms.

A method for laying weft thread is known to be used at present in needlelooms, wherein the feeding and the receiving laying needles mutuallyreciprocate by means of interconnected drives to pass the weft thread atthe moment of their closest approach.

In order to realize this method, the needles are placed on either sideof the weaving width of the loom and simultaneously enter the warp shedso as to transfer the weft thread from one needle to the other midwaybetween the starting points of their reciprocating motion with the aidof a forced and suction air jets, or mechanical grips.

In these conventional methods, the time of contact between the needlesor the period of standstill at the moment of their closest approachrequired for passing the weft thread is too short which often involvesfailure to catch the weft thread, and hence adversely affects thequality of manufactured fabric.

In the pneumatic method for transferring the weft thread from one needleto the other, the thread from the needle with the forced air jet mustemerge well before the needles meet, since the time of contact being tooshort and moving apart of the needles too rapidly the weft thread may bemissed by the suction air jet of the other needle, thus failing toaccurately pass the weft thread.

The weft thread emerging from the needle before both needles meet maycatch on the warp threads or miss the other needle, thus causing faultsin weaving, such as mispicks, loop-knots, and double threads.

When passing the thread by means of mechanical grips, a very briefcontact of the needles also causes frequent failure to catch the weftthread.

SUMMARY OF THE INVENTION It is an object of the present invention toeliminate the aforesaid disadvantages.

Another object of the present invention is to provide a method forlaying thread into the warp shed allowing an extension of the time ofcontact of the needles when passing the weft thread from one needle tothe other without reducing their speed or affecting the working capacityof the loom.

With these and other objects in view, in the method for laying weftthread in the warp shed of a loom, wherein the feeding and the receivinglaying needles reciprocate with respect to each other by means ofinterconnected drives to pass the weft thread at the moment of theirclosest approach, according to the invention, the needles meet at themidpoint of the distance between the starting points of theirreciprocating motion for which purpose the needles are made different inlength, and the shorter needle is introduced into the warp shed with atime lag relative to the moment of introducing into the shed the longerneedle which, at the moment of its maximum advance into the warp shed,approaches the shorter needle, moving toward it, as close as possible,and as the longer needle starts returning to its initial position, theshorter needle, continuing its stroke into the warp shed, follows thelonger needle, the time of movement of the needles in one directionbeing proportional to the value of the time lag, and, after the shorterneedle advances into the warp shed to a maximum, the needles return totheir initial positions leaving the warp shed at the same time.

Such an embodiment of the needles and their simultaneous movement in onedirection within a certain length make it possible to extend the time ofcontact of the needles, thus providing more favorable conditions forpassing the thread from one needle to the other, which enabled tosignificantly reducethe amount of fabric discarded on account ofmispicks, loops, and double threads.

The invention is further characterized by that the total length of bothneedles exceeds the distance between the starting points of theirreciprocating movement, thus making the needles meet at the midpoint ofthe weaving width of the loom and move in the same direction while theweft thread is-passed from one needie to the other.

Moreover, the invention is also characterized by the fact that thelonger needle is introduced into the warp shed faster than the shorterneedle, thus allowing for a simultaneous withdrawal of the needles fromthe warp shed without increasing the operating cycle time to lay oneweft thread, and hence, without affecting the speed of the needles andthe working capacity of the loom.

An extension of the time of contact of the needles during their closestapproach for transferring the weft thread from the feeding needle to thereceiving needle will thus permit of: significantly improving theconditions for catching the weft; sharply reducing the number ofmispicks, loops, and double threads in the fabric; improving the qualityof fabric; widening the variety of manufactured fabrics; enhancing theworking capacity of the needle loom by stepping up its working speeds asthe conditions for laying the weft thread have been improved.

BRIEF DESCRIPTION OF THE DRAWINGS A better appreciation of the inventionwill be had from the following detailed description of one of itsembodiments, taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a sectional view of a device in a loom for laying weft threadby the method according to the invention;

FIG. 2 is a schematic representation of the position of the needles atthe moment of their closest approach; and

FIG. 3 is a schematic representation of the position of the needles atthe starting moment of their separation as they move toward theirinitial positions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The device for layingweft thread in the warp shed of a loom consists of two laying needles Iand 2 (FIGS. 1, 2) mounted on either side of the weaving width of theloom, the needle 1 receiving the thread and the needle 2 feeding it, andinterconnected drives 3 and 4 which impart to the needles 1 and 2,respectively, reciprocating motions toward each other across the weavingwidth of the loom. The drives 3 and 4 may be of various designs so longas they can enable the needles to reciprocate, only one embodimentthereof, viz. a planetarygear drive, will be discussed below.

The needles 1 and 2 are made different in length, thus the receivingneedle I has a length l and the feeding needle 2 has a length I, so thatl l while the total length L of the needles (FIG. 3) exceeds thedistance L, (FIG. 1) between the starting points A and B of theirreciprocating moement, the difference in lengths of the needles 1 and 2accounting for their closest approach at the midpoint of the distance LEach of the drives 3 and 4 comprises a sun gear 5, a planet pinion 6,and two idle gears 7 each engaging the gears and 6.

The'fixed sun gear 5 is disposed on'a shaft 8 secured wherein is apinion carrier 9 articulated to axles 10 of the idle gears 7.

One of the ends of a lever 12 is articulated to an axle ll of the planetpinion 6, the free ends of the levers 12 in each drive 3 and 4 beinghinged to the ends of the needles 1 and 2, respectively.

The diameters of the sun gear 5, the planet pinion 6, and the idle'gearsof the drive 4 are somewhat bigger than those of the respective gears ofthe drive 3, and both the lever 12 and the pinion carrier 9 of the drive4 are slightly longer than those of the drive 3, all this accounting fora somewhat higher linear speed of the needle 2 relative to that of theneedle 1 and, consequently, ensuring a simultaneous withdrawal of theneedles 1 and2 from the warp shed.

The kinematic coupling of the drives 3 and 4 is accomplished through amain shaft 13 of the loom (FIG. 1) on whose ends there aresecured bevelgears 14 which mesh with bevel gears 15 mounted on the shafts 8 of thesun gears 5 of the drives 3 and 4.

Fixed on the main shaft 13 is a cam 16 which, through a shackle 17 withrollers and a rocker shaft 18, sets a reed 19 into swinging motion whichreed beats up the weft thread to the fell.

In order to provide for a normal thread passage from one needle to theother with a specified length of the needles, the drive 3 of the shorterneedle 1 should introduce it into the shed with a time lag relative tothe moment the longer needle 2 is inserted into the shed by the drive 4.

This can be realized in various ways, for instance, by actuatingthedrive 3 somewhat later than the drive 4, or actuating the drives at thesame time with the drive 3 running idly during the time lag, i.e. mostdifferent alternatives are here possible determined primarily by thedrive design or by the loom servicing conditions.

Regardless of the means for achieving this time lag, the

drive 4 of the longer needle 2 must ensure its insertion into the warpshed to a maximum, while the drive 3 must ensure the closest approach ofthe shorter'needle 1 to the longer needle and a continuation of itsadvance into the warp shed, and as the longer needle 2 starts returningto its initial position, the shorter needle 1 should follow it, i.e.within a length a (FIG. 2) the needles 1 and 2 must move in the samedirection, the time of movement of the needles in one direction beingproportional to the time lag no matter which of the needles, the feedingor the receiving one, is shorter.

In the present example, the time lag is provided by displacing thepinion carrier 9 with the idle gears 7 and the planet pinion 6 of theneedle drive 3 through an angle [3 relative to the position of thecarrier 9 with the idle gears 7 and the planet pinion 6 of the drive 4,

4 which angle determines the time of movement of the needles in onedirection, i.e. the length a of their movement in the same direction.

The above-described device lays'the weft thread as follows.

Rotation from the main shaft 13 (FIG. 1) is, through bevel gears 14 and15, transmitted to the shafts 8 of the drives 3 and 4 of the needles 1and 2.

The sun gears 5 (FIG. 2), the idle gears 7 and the planet pinions 6convert by means of the pinion carriers 9 the rotary motion of the shaft8 into reciprocating motion of the levers 12 which move the needles 1and 2 in guides (not shown).

Since the carrier 9, the idle gears 7, and the planet gear 6 in thedrive 3 are displaced through an angle [3 relative to the position ofthe carrier 9, the idle gears 7, and the planet pinion 6 in the drive 4,the needle 2 enters the warp shed somewhat earlier and faster than theneedle 1. As the needle 2 has a length l, exceeding the length l of theneedle 1, the closest approach of these needles is at the midpoint ofthe distance L between the starting points A and B of theirreciprocating movement, and at the moment of the maximum advancement ofthe longer needle 2 into the warp shed the shorter needle 1 continuesits movement into the warp shed and approaches the longer needle 2.

At this instance,the needle 2, the carrier 9, and the lever 12 of thedrive 4 are arranged in one line, whereas the carrier 9 of the drive 3is still at an angle [3 to the path of the needle 1, therefore as thelonger needle 2 starts returning to its initial position, the shorterneedle 1 follows it. In other words, within the length a, the needles 1and 2 move in the same direction (the direction of movement of theneedles is indicated by arrows in FIGS. 2 and 3), the time of theirmovement in one direction being proportional to the value of the angle5. When the shorter needle 1 advances to a maximum into the warp shed,the needle 1, the carrier 9, and lever 12 of the drive 3 are arranged inone line, whereas the carrier 9 of the drive 4 is at an angle a" to thepath of th needle 2. a

At the moment of the closest approach of the needles 1 and 2 and allalong the length a of their movment in one direction, the weft thread istransferred from one needle to the other, i.e. thetime of contact ofthese needles increases on account of their moving in the samedirection, which in turn improves the conditions for catching the weftthread. Once such movement of the needles is achieved, it makes nodifference whether the thread is transferred by mechanical grips or byan air jet. If the weft thread is to be transferred by an air jet, thereceiving needle 1 should advisably be shorter than the feeding needle2.

As the linear speed of the needle 2 is somewhat higher than that of theneedle 1, they return to their initial positions leaving the warp shedat the same time.

After the needles 1 and 2 (FIG. 1) return to their initial positions,the laid weft thread is beaten up by the reed 19 to the fell, and thenext portion 20 of the weft thread (FIG. 2) is fed into the needle 2from a bobbin 21 through a measuring mechanism 22 of a conventionaldesign provided with a compensator 23.

What is claimed is: r

1. A method for laying weft thread in the warp shed of a loom, saidmethod comprising the steps of:

reciprocating a feeding needle and a receiving laying needle in the warpshed with respect to each other to transfer the weft thread at themoment of their closest approach; effecting the needles to meet at themidpoint of the distance between the initial positions of theirreciprocating movement, the needles being made different in length forthis purpose; introducing the shorter one of the needles into the warpshed with a time lag relative to the moment of insertion into the shedof the longer one of the needles which, at the time of its maximumadvancement into the warp shed, approaches the shorter one of theneedles and moves toward it as close as possible; returning the longerone of the needles to its initial position, while the shorter one of theneedles continues its movement into the warp shed and follows the longerone of the needles, the time of movement of the needles in one directionbeing proportional to the value of the time lag; returning the needlesto their initial positions after the shorter one of the needles hasadvanced to a maximum into the warp shed; during the return of theneedles to the initial positions, withdrawing them from the warp shed atthe same time; and realizing the reciprocation of the needles by meansof interconnected drives.

2. A method as claimed in claim 1, providing the total length of bothneedles to exceed the distance between the initial positions of theirreciprocating movement.

3. A method as claimed in claim 1, providing the longer one of theneedles to enter into the warp shed at a faster speed than the shorterone of the needles.

1. A method for laying weft thread in the warp shed of a loom, saidmethod comprising the steps of: reciprocating a feeding needle and areceiving laying needle in the warp shed with respect to each other totransfer the weft thread at the moment of their closest approach;effecting the needles to meet at the midpoint of the distance betweenthe initial positions of their reciprocating movement, the needles beingmade different in length for this purpose; introducing the shorter oneof the needles into the warp shed with a time lag relative to the momentof insertion into the shed of the longer one of the needles which, atthe time of its maximum advancement into the warp shed, approaches theshorter one of the needles and moves toward it as close as possible;returning the longer one of the needles to its initial position, whilethe shorter one of the needles continues its movement into the warp shedand follows the longer one of the needles, the time of movement of theneedles in one direction being proportional to the value of the timelag; returning the needles to their initial positions after the shorterone of the needles has advanced to a maximum into the warp shed; duringthe return of the needles to the initial positions, withdrawing themfrom the warp shed at the same time; and realizing the reciprocation ofthe needles by means of interconnected drives.
 2. A method as claimed inclaim 1, providing the total length of both needles to exceed thedistance between the initial positions of their reciprocating movement.3. A method as claimed in claim 1, providing the longer one of theneedles to enter into the warp shed at a faster speed than the shorterone of the needles.